[Helm]

Buy 500 matchboxes. Carefully pry off the rough side from all the boxes, and also empty them all so you have a big pile of matches in front of you. Carefully remove all the heads from the matches. Then, discard the destroyed boxes, and matchsticks. All you'll need will be the matchheads and the rough sides from the boxes. Now start neatly inserting a quantity of matchheads (let's say about 20, give or take) and one rough box side alternatively inside your vagina or anus (your choice. I think either would work as well) until you have no more matchheads or rough sides. Then jump up and down furiously, thusly generating the neccessary friction between the matchheads and rough sides so that your cunt, or anus, or both if you decided to go all out bursts into a series of scathing internal explosions.

Repeat as required.